diff --git a/app/assets/images/icons.svg b/app/assets/images/icons.svg
index b209a135e..d3e575f3c 100644
--- a/app/assets/images/icons.svg
+++ b/app/assets/images/icons.svg
@@ -221,6 +221,32 @@
       <path d="M11 16m-1 0a1 1 0 1 0 2 0a1 1 0 1 0 -2 0"/>
       <path d="M12 16l0 -5l2 1"/>
     </symbol>
+    <symbol viewBox="0 0 24 24" stroke-linecap="round" stroke-linejoin="round" id="icon--file-type-docx">
+      <path d="M14 3v4a1 1 0 0 0 1 1h4"/>
+      <path d="M5 12v-7a2 2 0 0 1 2 -2h7l5 5v4"/>
+      <path d="M2 15v6h1a2 2 0 0 0 2 -2v-2a2 2 0 0 0 -2 -2h-1z"/>
+      <path d="M17 16.5a1.5 1.5 0 0 0 -3 0v3a1.5 1.5 0 0 0 3 0"/>
+      <path d="M9.5 15a1.5 1.5 0 0 1 1.5 1.5v3a1.5 1.5 0 0 1 -3 0v-3a1.5 1.5 0 0 1 1.5 -1.5z"/>
+      <path d="M19.5 15l3 6"/>
+      <path d="M19.5 21l3 -6"/>
+    </symbol>
+    <symbol viewBox="0 0 24 24" stroke-linecap="round" stroke-linejoin="round" id="icon--file-type-ppt">
+      <path d="M14 3v4a1 1 0 0 0 1 1h4"/>
+      <path d="M14 3v4a1 1 0 0 0 1 1h4"/>
+      <path d="M5 18h1.5a1.5 1.5 0 0 0 0 -3h-1.5v6"/>
+      <path d="M11 18h1.5a1.5 1.5 0 0 0 0 -3h-1.5v6"/>
+      <path d="M16.5 15h3"/>
+      <path d="M18 15v6"/>
+      <path d="M5 12v-7a2 2 0 0 1 2 -2h7l5 5v4"/>
+    </symbol>
+    <symbol viewBox="0 0 24 24" stroke-linecap="round" stroke-linejoin="round" id="icon--file-type-xls">
+      <path d="M14 3v4a1 1 0 0 0 1 1h4"/>
+      <path d="M5 12v-7a2 2 0 0 1 2 -2h7l5 5v4"/>
+      <path d="M4 15l4 6"/>
+      <path d="M4 21l4 -6"/>
+      <path d="M17 20.25c0 .414 .336 .75 .75 .75h1.25a1 1 0 0 0 1 -1v-1a1 1 0 0 0 -1 -1h-1a1 1 0 0 1 -1 -1v-1a1 1 0 0 1 1 -1h1.25a.75 .75 0 0 1 .75 .75"/>
+      <path d="M11 15v6h3"/>
+    </symbol>
     <symbol viewBox="0 0 24 24" stroke-linecap="round" stroke-linejoin="round" id="icon--folder">
       <path d="M5 4h4l3 3h7a2 2 0 0 1 2 2v8a2 2 0 0 1 -2 2h-14a2 2 0 0 1 -2 -2v-11a2 2 0 0 1 2 -2"/>
     </symbol>
diff --git a/app/helpers/icons_helper.rb b/app/helpers/icons_helper.rb
index 9a2ae2d98..794e5bd46 100644
--- a/app/helpers/icons_helper.rb
+++ b/app/helpers/icons_helper.rb
@@ -139,6 +139,16 @@ module IconsHelper
         when 'text'
           %w(markdown plain x-textile).include?(subtype) ? 'text-plain' : nil
         when 'video' then 'movie'
+        else
+          # MIME type mapping
+          {
+            # Microsoft Office Open XML documents
+            # Do not add legacy Office formats (.doc, .xls, .ppt) here because
+            # Redmine does not provide attachment preview for these formats.
+            'application/vnd.openxmlformats-officedocument.presentationml.presentation' => 'file-type-ppt',
+            'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' => 'file-type-xls',
+            'application/vnd.openxmlformats-officedocument.wordprocessingml.document' => 'file-type-docx'
+          }[mime.to_s]
         end
     end
     icon_name || 'file'
diff --git a/config/icon_source.yml b/config/icon_source.yml
index 98fe995ab..4979d75b3 100644
--- a/config/icon_source.yml
+++ b/config/icon_source.yml
@@ -250,3 +250,9 @@
   svg: movie
 - name: file-music
   svg: file-music
+- name: file-type-docx
+  svg: file-type-docx
+- name: file-type-xls
+  svg: file-type-xls
+- name: file-type-ppt
+  svg: file-type-ppt
diff --git a/test/helpers/icons_helper_test.rb b/test/helpers/icons_helper_test.rb
index 061e5bede..07a656222 100644
--- a/test/helpers/icons_helper_test.rb
+++ b/test/helpers/icons_helper_test.rb
@@ -225,6 +225,12 @@ class IconsHelperTest < Redmine::HelperTest
     assert_equal 'application-pdf', icon_for_mime_type('application/pdf')
     assert_equal 'text-plain', icon_for_mime_type('text/markdown')
     assert_equal 'text-plain', icon_for_mime_type('text/plain')
+    assert_equal 'file-type-docx',
+                 icon_for_mime_type('application/vnd.openxmlformats-officedocument.wordprocessingml.document')
+    assert_equal 'file-type-xls',
+                 icon_for_mime_type('application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')
+    assert_equal 'file-type-ppt',
+                 icon_for_mime_type('application/vnd.openxmlformats-officedocument.presentationml.presentation')
   end
 
   def test_icon_for_mime_type_should_return_icon_for_top_level_types